Active Region Magnetic Structure Observed in the Photosphere and Chromosphere

The magnetic flux above sunspots and plage in NOAA (National Oceanic and Atmospheric Administration) Active Region 8299 has been measured in the photosphere and the chromosphere. We investigate the vertical magnetic structure above the umbrae, penumbrae and plage regions using quantitative statistical comparisons of the photospheric and chromospheric vector magnetic flux data. The results include: (1) a decrease in flux with height, (2) the direct detection of the superpenumbral canopy in the chromosphere, (3) values for dB/dz which are consistent with earlier investigations when derived from a straight difference between the two datasets but quite low when derived from the delta x B = 0 condition, (4) a monolithic structure in the umbra which extends well into the upper chromosphere with a very complex and varied structure in the penumbra and plage, as evidenced by (5) a uniform magnetic scale height in the umbrae with an abrupt jump to widely varying scale heights in the penumbral and plage regions. Further, we find (6) evidence for a very large (delta z approximately equals 3Mm) height difference between the atmospheric layers sampled in the two magnetograms, almost a factor of three larger than that implied by atmospheric models. We additionally test the apropriateness of using photospheric magnetic flux as a boundary for field-line extrapolations, and find a better agreement with observed coronal structure when the chromospheric flux is used as a boundary.